C 1500 Truck 2WD V8-305 5.0L VIN F 4-bbl (1985)
Technical Service Bulletin # 88T1845
Date: 890101
Brakes - Pull/Lead When Braking
GMC NUMBER:
88-T-184
GROUP:
5 - Brakes
DATE:
January, 1989
CORPORATE
NUMBER:
865006R
SUBJECT:
LEAD WHILE BRAKING
MODELS:
1984-86 K1-2 AND 1987-88 V1-2
A condition described as directional lead (either right or left) while braking may be addressed on the models listed above by careful inspection,
adjustment or repair of the vehicle's tires, suspension, steering or brake components. The following procedures have been developed to systematically
address the area(s) that should be inspected and adjusted. Evaluation of a vehicle's brake performance is not intended to be made with the vehicle
operator's hands removed from the steering wheel. Vehicles that exhibit directional bias under these conditions are not considered to exhibit brake lead.
Before road testing the vehicle, perform the following services:
NOTICE:
Follow the service procedures in the 1988 Light Duty Service Manual X-8832 unless noted differently.
Preliminary Inspection:
^
Inspect tires for excessive, uneven wear - replace if necessary.
^
Equalize tire pressures.
^
Torque leaf spring-to-axle U-bolts to high limit
of specification (150 ft.lbs. or 2 03 N-m). See Section 3C for tightening order.
^
Equalize parking brake adjustment.
^
Adjust rear service brakes to .030" running clearance.
^
Inspect and record front end alignment readings - adjust total toe to specifications (.0" to .14"). Inspect caliper brake line bolt (#34, page 5A8,
Figure 4, 1988 Service Manual X-8832) for mislocation of orifice. The orifice should be located in the unthreaded part of the bolt. If the orifice is
located in a threaded portion of the bolt, then the bolt must be replaced.
NOTICE:
After the preceding inspections and/or adjustments have been made, the vehicle should be road tested to determine if a lead still exists.
Vehicles that lead may lead either right or left when the brakes are applied.
Make all stops on a dry, level (no crown), clean roadway.
FIGURE 1 - CALIPER/KNUCKLE CLEARANCES
IMPORTANT!
EACH APPLICABLE STEP MUST BE THOROUGHLY COMPLETED TO EFFECT A LASTING REPAIR. FAILURE TO COMPLETE THE
PROCEDURE EXACTLY AS WRITTEN MAY RESULT IN AN UNSATISFACTORY REPAIR.
